1. Field of the Invention
The present invention relates to a control apparatus for a hybrid vehicle driven by an engine and a motor. In particular the invention relates to a control apparatus for a hybrid vehicle, which regulates the deceleration regeneration amount by a motor according to traveling conditions.
This application is based on Japanese Patent Application, Unpublished, No. Hei 11-280682, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Heretofore there is known a hybrid vehicle incorporating a motor in addition to an engine as a drive source for vehicle propulsion.
For one type of such hybrid vehicle, there is a parallel hybrid vehicle where the motor is used as an auxiliary drive source for assisting the output from the engine. With this parallel hybrid vehicle, for example at the time of acceleration, the output from the engine is assisted by means of the motor, while at the time of deceleration, various control is carried out such as performing charging of a battery by deceleration regeneration, so that the remaining charge (electrical energy) of the battery can be maintained while satisfying the requirements of the driver. (For example, as disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 7-123509.)
According to the control apparatus for the above-mentioned conventional hybrid vehicle, for example, in a situation where the degree of throttle opening (e.g. the extent of the throttle opening) is fully closed state, or fuel supply to the engine is stopped such as when traveling at high speed, the hybrid vehicle is decelerated by the two actions of regeneration by the motor and engine braking. Therefore, if the deceleration of the vehicle is as the driver has estimated, there is no problem, however, if the deceleration is greater than estimated, against the driver""s intention, for example, when there is a vehicle traveling ahead, if the distance from the forward vehicle is increasing, a situation may occur when the accelerator pedal is pressed again with the intention of following the vehicle traveling ahead. In this case, the frequency of regeneration the motor is reduced, the frequency of stopping fuel supply is reduced, and there is a problem of deterioration in fuel consumption rate.
The present invention takes into consideration the above situation, with the object of providing a control apparatus for a hybrid vehicle that can improve fuel consumption rate by regulating the regeneration amount by the motor to make appropriate the perceived deceleration of a vehicle.
To solve the abovementioned problem and achieve this object, a control apparatus for a hybrid vehicle (hybrid vehicle 10 in an embodiment as mentioned later) comprising: an engine (engine E) for outputting a propulsion force for a vehicle, a motor (motor M) for assisting the output from the engine depending on the driving conditions of the vehicle, and a storage unit (battery 22) for storing generated energy when the motor is used as a generator under the output from the engine, and regenerated energy obtained from regeneration of the motor at the time of vehicle deceleration, comprising: a remaining charge computing device (battery ECU 13) for computing the remaining charge of the storage unit, a speed detector (vehicle speed sensor S1) for detecting the speed of the vehicle, a regeneration amount setting device (step S202 and step S203) for setting the amount to be regenerated from the motor, and a regeneration amount reduction device (step S207) for, at the time of reducing the speed of the vehicle when a degree of throttle opening of the vehicle is fully closed state, or fuel supply to the engine is stopped, in the case where the remaining charge is computed by the remaining charge computing device to be greater than or equal to a predetermined remaining charge, and the speed is detected by the speed detector to be greater than or equal to a predetermined speed, multiplying the amount to be regenerated by a predetermined reduction coefficient.
According to the control apparatus for a hybrid vehicle of the above construction, in the case where the remaining battery charge of the storage unit is greater than or equal to a predetermined value, and the speed of the vehicle is greater than or equal to a predetermined speed, the regeneration amount by regeneration of the motor is reduced to prevent excessive deceleration of the hybrid vehicle, and the deceleration perceived by the driver is made appropriate. Consequently, unnecessary pressing of the accelerator pedal by the driver can be controlled. As a result, a decrease in frequency of regeneration of the motor can be prevented, and deterioration of fuel consumption ratio can be prevented by a decrease in the frequency of stopping the fuel supply.
Furthermore, the control apparatus for the hybrid vehicle of the present invention of a second aspect further comprising: a brake operation detector (brake switch S4) for detecting the brake operation of the vehicle, and a regeneration amount reduction inhibiting device (step S201) for, in the case where the brake operation detector detects that the brake is working, inhibiting the operation of the regeneration amount reduction device.
According to the control apparatus for a hybrid vehicle of the above construction, in the case where the brake pedal is pressed, it is determined that deceleration of the hybrid vehicle is requested by the driver, and reduction of the regeneration amount from the regeneration of the motor is inhibited. Consequently, the driver""s intention is accurately reflected, and the hybrid vehicle can be decelerated, and regenerated energy can be obtained without unnecessary reduction of the regeneration amount.
Moreover, according to the control apparatus for a hybrid vehicle of the present invention of a third aspect, the hybrid vehicle is provided with an automatic transmission (transmission T) and gear shift schedule controller (CVTECU 14) for changing a gear shift schedule according to traveling conditions of the vehicle, and the regeneration amount reduction inhibiting device, in the case where the gear shift schedule controller is operating, or a deceleration ratio of the automatic transmission is larger than a predetermined deceleration ratio, inhibits the operation of the regeneration amount reduction device.
According to the control apparatus for a hybrid vehicle of the above construction, in the case where gear shift control is performed by the automatic transmission or the gear shift schedule controller, by inhibiting reduction of the regeneration amount, for example, it is possible to avoid disturbing the control for setting a large deceleration ratio to decelerate the hybrid vehicle at the time of traveling down a slope, and for changing the gear shift schedule to improve the effect of the engine brake.